Using the State Hook to Save Component State in React

Last Updated on June 17, 2024

useState is a Hook that allows you to have state variables in functional components. You pass the initial state to this function and it returns a variable with the current state value (not necessarily the initial state) and another function to update this value.

useState() should only be used inside a functional component.

import React, { useState } from 'react';

function Example() {
  // Declare a new state variable, which we'll call "count"  
const [count, setCount] = useState(0);
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

Equivalent Class Example

class Example extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  render() {
    return (
      <div>
        <p>You clicked {this.state.count} times</p>
        <button onClick={() => this.setState({ count: this.state.count + 1 })}>
          Click me
        </button>
      </div>
    );
  }
}

References
https://reactjs.org/docs/hooks-state.html

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